Is there a proper place to store a high level description of a database? Something along the lines of "This database is used to store XYZ for use by ABC". It's not necessarily information one would need to query, but something that would useful for someone administering the system (i.e. me in a few months when I'm trying to remember what I was trying to accomplish a few months ago.).
This seems like something that someone would have asked before (or information that is readily findable), but none of my searching came up with anything relevant. Most of what I found was for displaying the structure of the database itself.
Comment metadata is not available for MySQL databases, but you can create a table to store some comments: (I have this table in a generic tools database)
-- Create a table to store db name and fields as need.
create table dbinfo(
id int not null primary key auto_increment,
db_name varchar(64) not null collate utf8_bin,
db_comment varchar(255),
unique (db_name)
) default charset utf8;
To fill/update dbinfo table with current databases:
insert into dbinfo (db_name)
select SCHEMA_NAME
from INFORMATION_SCHEMA.SCHEMATA
where SCHEMA_NAME not in (select db_name from dbinfo);
You will only need to maintain dbinfo table until MySQL enables database comments.
Related
I am able to create a table manually in SQL Server by checking columns from MySQl table. And then able to move data from MySQL to SQL Server table.
Example: MySQL table = Employee
Describe Employee;
Output
Field, Type, Null, Key, Default, Extra
EmpId int(10) NO PRI 0
Name varchar(100) YES
Age int(10) YES 18
EmailId varchar(100) NO
Using this I am creating same table in SQL Server
Drop table MsSQLdb..Employee;
CREATE TABLE Employee (
EmpId int NOT NULL PRIMARY KEY DEFAULT 0,
Name varchar(100),
Age int de,
Name varchar(100) NOT NULL DEFAULT 18
);
Now using OpenQuery to copy the data from MySQL to SQL Server :
select EmpId,Name,Age,EmailId into MsSQLdb..Employee
from
OPENQUERY(LinkedServer, 'SELECT EmpId,Name,Age,EmailId FROM mySQL_db.Employee')
But, daily my mySQL_db.Employee table gets more columns or less. So daily I need to manually Map this columns in the above queries to redo the task. Is there any dynamic way for this task?
I have around 40-tables and each table have around 30+ columns. so looking for any a dynamic way.
You can go for SELECT * INTO for loading data into tables. More on SELECT
I assume that you are fine for DROP & RECREATE and simple scenario of loading data. You might not get right datatype as datatype is automatically decided by SQL Server based on initial set of rows.
DROP TABLE dbo.Employee;
SELECT * INTO dbo.Employee
from
OPENQUERY(LinkedServer, 'SELECT * FROM mySQL_db.Employee')
Indexes, constraints, and triggers defined in the source table are not
transferred to the new table, nor can they be specified in the
SELECT...INTO statement. If these objects are required, you can create
them after executing the SELECT...INTO statement.
I'm currently trying to find a way to separate the mysql export function (using phpmyadmin and/or shell)
Following situation:
I have two databases which were the same at some state but over time only one got updated. So for example:
- database1 has table "users" with columns "UID" and "username"
- database2 has table "users" with columns "UID" "username" and "status"
Now i want to export database2 and import it to database1. database2 contains data I DONT need anymore. But database1 contains important data. So I need something that gives me the possibility to somehow "merge" these databases without data loss on database1 and without merging data from database2.
The merge should look if the table exists, if not -> create it
The merge should look if the columns exist in the table, if not -> create it
What I have tried so far:
I've first tried it with the inbuilt PHPmyadmin export function (advanced options). This would give me the following result:
CREATE TABLE IF NOT EXISTS `users` (
`UID` int(11) NOT NULL,
`username` varchar(25) NOT NULL,
`status` int(2) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
When I import this, of course, nothing special will happen since the table already exists and so the 'status' column does not get created.
On my research I found a possibility to export a database separated from table creation using shell using the command (blacked out database name and user/pass):
mysqldump -t --insert-ignore --skip-opt -u USER -p PASSWORD -h 127.0.0.1 database > database.sql
But this gives me an insert option with data (which I dont need)
INSERT IGNORE INTO `users` VALUES (1,"bla",1);
Is there any different possibility?
Sure I know I could write it by hand to alter the columns into the table but it sure has to be automatic since its not only the table I named in the example.
To be 100% clear what I'm trying to achieve, a pseudo handwritten sql script:
CREATE TABLE IF NOT EXISTS 'users';
For every column -> IF NOT EXISTS column in 'users' -> ALTER TABLE 'users' ADD column def;
You can use MySQLWorkBench as well. Look video instruction
I need to create a table with a file or anything, everything needs to be done as a sql script.
Can someone help me create a table without a csv file,
The name of the table is "videos"
The rows will be:
unique id
title
minutes
URL
When creating table to database via script you need to create a file where you will define structure of table with DDL (Data definition language).
For example
Create file table.sql. Open file and use CREATE TABLE statement for table creation.
CREATE TABLE videos(
id INT NOT NULL AUTO_INCREMENT,
minutes INT NOT NULL,
title VARCHAR(255) NOT NULL,
url VARCHAR(255) NOT NULL,
PRIMARY KEY ( id )
);
Afterwards you can run this script in many different ways. For example in Linux based operating systems you can run script with command mysql in form mysql -u user -p database_name < table.sql, where user is your username and database_name is name of database for which you want to create table.
I'm trying to create a data warehouse.
Is it possible to populate a table in db1, from data in db2.
For example
Corporate Database Table Route
CREATE TABLE ROUTE (
RouteID INTEGER(4) PRIMARY KEY,
RouteName VARCHAR (50) NOT NULL,
BoardingStop VARCHAR (50) NOT NULL,
AlightingStop VARCHAR (50) NOT NULL
);
Insert Information
INSERT INTO `ROUTE` (`RouteID`,`RouteName`,`BoardingStop`,`AlightingStop`)
VALUES (1,"ab","B","C")
Data warehouse table dimRoute
CREATE TABLE DimROUTE (
RouteID INTEGER(4),
RouteName VARCHAR (50) NOT NULL,
BoardingStop VARCHAR (50) NOT NULL,
AlightingStop VARCHAR (50) NOT NULL,
PRIMARY KEY(RouteID)
);
Populate the above table with data from the first table.
You can copy from one table into another table with INSERT INTO ... SELECT. See docs here: http://dev.mysql.com/doc/refman/5.7/en/insert-select.html
You can copy between tables in different databases on the same MySQL instance, provided you have privileges to both database. Just use databasename.tablename syntax:
INSERT INTO warehouse.DimRoute
SELECT * FROM corporate.Route;
If the databases are hosted on different MySQL instances, you can dump data from the corporate instance and import to the data warehouse instance using mysqldump. Since your table is named differently in the data warehouse, this is a little bit tricky.
You could restore the data to its original table name, and then rename the table:
$ mysqldump --host=corporate corp_dbname ROUTE > route-dump.sql
$ mysql --host=datawarehouse dw_dbname < route-dump.sql
$ mysql --host=datawarehouse -e "RENAME TABLE ROUTE TO DimROUTE" dw_dbname
(I'm leaving out user/password options for brevity, but I suggest you use the config file for those.)
You just need a couple of queries to clone a table (with its indexes and keys) then populate it with the records:
CREATE TABLE DimROUTE LIKE ROUTE;
INSERT DimROUTE SELECT * FROM ROUTE;
Demo SQL Fiddle
Yes, you can. The technique you want is called Extract, Transform and Load (ETL). There are a number of tools you can use, which will help you automate and organise the process. Or you can roll your own solution.
It is quite common for reporting databases to be feed by other databases in this fashion.
I want to merge 5 identical-schema (okay, they are not exactly identical but I can edit the field names to make them identical) MySQL databases into one database. Is there any easy way?
CREATE TABLE `users` (
`name` VARCHAR (50) COLLATE utf8_turkish_ci DEFAULT NULL,
`surname` VARCHAR (50) COLLATE utf8_turkish_ci DEFAULT NULL,
`telephone` VARCHAR (50) COLLATE utf8_turkish_ci DEFAULT NULL,
PRIMARY KEY (`id`),
) ENGINE = MyISAM AUTO_INCREMENT = 1000 DEFAULT CHARSET = utf8 COLLATE = utf8_turkish_ci PACK_KEYS = 0 ROW_FORMAT = DYNAMIC
If the tables are exactly the same with column names/types and are named
user1
user2
user3
user4
user5
there are two approaches to handle this:
APPROACH #1 : Load the data into one table
CREATE TABLE user LIKE user1;
INSERT INTO user (name,surname,telephone,...)
SELECT name,surname,telephone,... FROM user1;
INSERT INTO user (name,surname,telephone,...)
SELECT name,surname,telephone,... FROM user2;
INSERT INTO user (name,surname,telephone,...)
SELECT name,surname,telephone,... FROM user3;
INSERT INTO user (name,surname,telephone,...)
SELECT name,surname,telephone,... FROM user4;
INSERT INTO user (name,surname,telephone,...)
SELECT name,surname,telephone,... FROM user5;
If the id is auto_increment all rows get new ids.
APPROACH #2 : Use the MERGE Storage Engine
CREATE TABLE user LIKE user1;
ALTER TABLE user
ENGINE=Mrg_MyISAM
UNION=(user1,user2,user3,user4,user5)
;
Give it a Try !!!
There's no easy way to do this.
You could attempt to alter your tables within the different databases to bring them to be in the most similar format.
Additionally, you could use statements such as
Create table as select
in order to further format the data.
Than you would have to do a MYSQL DUMP of all your databases.
Select only the create statements from the database schema you are interested in following, and add your insert statements (for the data) from all the different databases.
You may also have to perform text manipulation in Excel, or from with mysql in order to get the data in such a format that it is compatible and can be inserted in your final schema.
Any ETL tool, like Clover, would be well suited for your purpose. Just define your column mappings and you should be good to go. Leave a comment if you need further help.